World Book Encyclopedia

The World Book Encyclopedia is an American encyclopedia. World Book was first published in 1917. Since 1925, a new edition of the encyclopedia has been published annually. Although published online in digital form for a number of years, World Book is currently the only American encyclopedia which also still provides a print edition. The encyclopedia is designed to cover major areas of knowledge uniformly, but it shows particular strength in scientific, technical, historical and medical subjects.

World Book, Inc. is based in Chicago, Illinois. According to the company, the latest edition, World Book Encyclopedia 2024, contains more than 14,000 pages distributed along 22 volumes and also contains over 25,000 photographs.

World Book also publishes children's non-fiction and picture books under the Bright Connections Media imprint, and educational development and supplemental instructional resources through Incentive Publications by World Book.

World Book was founded in Chicago by publishers J. H. Hansen and John Bellow, who realized that existing encyclopedias were off-putting to readers. In 1915, they enlisted the help of Michael Vincent O'Shea, a professor of education at the University of Wisconsin.

The first edition of The World Book Encyclopedia was published (as simply The World Book) in 1917, by the Hanson-Roach-Fowler Company. "As a rule," wrote O'Shea, the founding editor, in the preface of that 1st edition, "encyclopedias are apt to be quite formal and technical. A faithful effort has been made in the World Book to avoid this common defect." The encyclopedia's name would later be shortened to its current name World Book.

In 1919, World Book became the property of W.F. Quarrie & Company. The new owners created an editorial board to help make sure the entries were aligned with what students studied, from kindergarten to high school.

In 1933, World Book exhibited at the Century of Progress Exposition in Chicago.

In 1945, World Book became the property of Field Enterprises.